A client device (e.g., a mobile wireless device) may be configured to passively listen to (snoop) transmit/receive exchanges (constituting a ranging exchange) between two access points on a computer network. The purpose of a ranging exchange is to measure or record times associated with transmitting and receiving messages between the two access points. The times can be used to determine a range (a distance) between the client device and the two access points. The client device may use the information obtained (e.g., timing information) from the ranging exchange between the two access points, along with other information the client device similarly obtains by listening to other ranging exchanges between other pairs of access points, to determine a location of the client device. Determining the location of a client device in this manner may be desirable, for example, when the client device is indoors without access to global positioning system (GPS) signals.